1. Field of the Invention
The invention is related to the field of materials handling technology and in particular to a conveying device with pusher elements.
2. Description of Related Art
In case of known conveying systems, which include belts or chains of elements of the same kind, the length of the belts or chains always has to be adapted to the length of the conveying device. The belts or chains have to be threaded into the conveying device and subsequently connected to form a circulating device and then tensioned. In case of belt-like conveying devices, in addition, an as flat as possible surface has to be formed to receive objects to be conveyed. Furthermore, for moving the installation, as little force as possible should have to be exerted.
In WO 2004/063059 A1 a conveying system is described, which conveys by pushing and pulling rigid lamellas with compressible elements in between. The compressible elements are pre-tensioned in the conveying direction, i.e., partially compressed, and are able to be guided around curves without any gaps occurring in the conveying system. The lamellas comprise laterally protruding teeth, so that they are capable of being driven by correspondingly shaped teeth of a driving means.
EP 0 488 296 A1 discloses a conveying device, in which individual carrier elements, which are not hooked together, are pushed through a guide-way. The carrier elements at both ends respectively comprise rollers, with which they roll-off in a guide-way. The carrier elements are cylindrically shaped or, in another embodiment, when they are pushed together, they form a fairly flat plane. In the last mentioned embodiment the carrier elements are distanced from one another by spacer elements. When the carrier elements are conveyed around a curve, the spacer elements rub together and therefore make the conveyance more difficult.
In FR 143 262 a rapidly and simply utilisable transport aid is described, which comprises several pairs of rollers respectively rotatable around an axis. The axes are connected together in the middle by a flexible belt. At the ends, the axes respectively comprise wheels with a larger diameter than the rollers. The transport aid is capable of being designed in any type of track, whereby the rollers serve as a rolling surface for loads. By means of the wheels, the transport aid is also capable of being displaced.
In WO 2005/113 391 and WO 2005/113392 no conveying systems, but rather roller bearings are disclosed. Present in these are circulating rollers for receiving high loads. These rollers rotate around an oval roller body and are spaced between one another by bodies running along with them. As in the case of a conventional roller bearing, the rollers on the one hand roll off on the roller body and on the other hand on a counter body, and so absorb a load force between the roller body and the counter body.
None of the known conveying devices comprises the required characteristics.